Light polymerization devices had long been conventionally known as is disclosed, for example, in U.S. Pat. No. 5,471,129.
A light polymerization device of the above-noted type is provided with a storage battery assembly, which is mounted in the handgrip of a hand-held device. To effect the charging of the storage battery assembly, a base station is provided and the grip of the hand-held device is inserted into corresponding receptacles in the base station for a charging operation. To increase the convenience and availability of the device, two corresponding receptacles are provided so that two hand-held devices can be disposed in the same base station, whereupon one of the hand-held devices is loaded or charged and the other is available for use.
An approach of the above-noted type offers, in fact, a large degree of convenience and availability. However, due to the two required hand-held devices, such an approach is comparatively expensive.
Moreover, it has long been known, in connection with hand-held devices in other technical areas such as, for example, storage battery-powered or cordless drills or cordless screwdrivers, to couple together a storage battery assembly configured as a compact unit and a hand-held device into which the storage battery assembly can be inserted and, as required, to exchange or, respectively, to charge, solely the storage battery assembly.
Such approaches avoid the necessity of a separate hand-held device. On the one hand, it is known that the storage battery assemblies experience a diminution of their quality during the course of the operating time. In this connection, the so-called memory effect is part of this phenomenon but, as well, so is the effect, which occurs toward the end of the operational life, of increasing self-discharging of the storage battery assembly.
U.S. Pat. No. 5,471,129 discloses various measures to limit the negative effect of such disadvantages upon light polymerization devices, among which is the measure of monitoring the capacity of the storage battery assembly. The corresponding monitoring switch is mounted, in this approach, in the hand-held device. However, in connection with a spaced separation of the storage battery assembly and the hand-held device, monitoring a storage battery assembly in this manner, which is based upon acquisition of the storage battery assembly loading and discharging curves, is not possible or, at the least, is not practical, as even storage battery assemblies manufactured at the same time can possess different properties, which come to the fore upon deployment of the respective storage battery assembly.
One approach known in connection with digital film cameras for avoiding this undesired phenomenon is to provide the storage battery assembly itself with a micro-controller, which acquires the actual parameters of the storage battery assembly and the changes thereof during its operational life and stores such information.
A particular disadvantage of the entire range of such storage battery assemblies including, as well, high-value lithium ion storage battery assemblies, is their weight.
If a hand-held device is to be operated in a cable-free or cordless manner, the use of a storage battery assembly (or at least a battery pack) is, on the other hand, unavoidable.
Dentists, who seek a lightweight hand-held operation in connection with the use of a light polymerization device for polymerizing dental material, prefer, because of the weight of the storage battery assemblies, hand-held devices having an electrical energy supply cable connected with the base station. Such hand-held devices have, also, long been known, whereby, in the meantime, comparatively light yet nonetheless highly flexible cables can be provided. It is also known to use hand-held devices with a selectively deployable power pack connection and additionally, to outfit such hand-held devices for the possible receipt of a storage battery assembly.
A solution of this type is disclosed, for example, in DE 41 16 604. However, a hand-held device of this type is not particularly amenable to hand-held operation, if the storage battery assembly is, for the purpose of weight saving, removed from the hand-held device, as the hand-held device can no longer be readily deployed.
In considering the acquisition of operational parameters of the storage battery assembly, it is desirable, in connection with light polymerization devices, to also acquire the quality of the light output itself. In this connection, light sensors have been suggested which at least approximately acquire the outputted light performance and monitor the same.
On the other hand, the outputted light performance represents the most important quality criteria of a light polymerization device. The use of conventional halogen glow lamps causes vaporization of substantial portions of the tungsten layer or coating on the filament, whereupon the light performance decreases.
Once a storage battery assembly-powered light polymerization device has now been in relatively long use, the light performance decreases at a regular rate as does, as well, the capacity of the charge accumulator in the storage battery assembly. These performance opposing trends during the course of a storage battery assembly's usage reinforce the risk of an incomplete hardening of dental restoration pieces, comprised of synthetic materials, in the mouth of a patient. In this regard, monomers occasionally remain in such restoration pieces and follow-up demands against the dentist or, respectively, the manufacturer of the light polymerization device, cannot be excluded.
Moreover, the heretofore known solutions have not exhibited particularly good flexibility in connection with hand-held operations and fail to satisfy the various requirement profiles of the customers. Also, the reliability of the polymerization process leaves, in part, something to be desired.